JP2790933B2 - Manufacturing method of heat exchanger fins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fin for a heat exchanger used for a heat exchanger such as a car cooler or a room cooler.

[0002]

2. Description of the Related Art Cooling fins used in a heat radiating portion of a heat exchanger such as a car cooler or a room cooler are:
A plurality of through holes with a predetermined height are provided in a metal plate such as a rectangular aluminum plate. The heat dissipating portion of the heat exchanger formed by such fins is formed by stacking a plurality of fins so as to match each of the colored through holes of each fin, and having a high thermal conductivity such as copper over these through holes. A metal conduit is inserted and integrated. As a method of manufacturing such fins for heat exchangers,
For example, Japanese Patent Application Laid-Open No. 49-103808 proposes a manufacturing method shown in FIG.

[0003] The manufacturing method shown in FIG. 3 includes the following steps. First, a perforation process and a burring process are performed on the metal plate 100 to form a perforation hole 101 whose periphery is surrounded by a protruding piece 102 (step (a)). The ironing process is performed to extend the protruding piece 102 while "ironing" while enlarging it, and to form a collar 104 having a predetermined height [steps (b) and (c)]. Such an ironing process is usually performed by “squeezing” the protruding piece 101 or the collar 103 by the outer wall surface of the punch and the inner wall surface of the die. In FIG. 3, the ironing process is performed in two stages, and the punches and dies used in each stage have different diameters. The collar 104 having a predetermined height thus obtained is bent at its tip to form a flange 105 [step (d)].

According to the manufacturing method shown in FIG. 3 (hereinafter sometimes referred to as an ironing method), since the ironing is performed while increasing the diameter of the perforated hole, a punch is formed around the resulting collar. No processing marks such as marks are generated,
Moreover, even with a hard metal plate, a through hole with a collar having a predetermined height can be obtained. By the way, in such an ironing processing method, it is necessary to perform while using a processing oil, and usually, a non-volatile oil is used as the processing oil. As described above, when the non-volatile oil is used during the ironing process, the non-volatile oil adheres to the obtained heat exchanger fins (hereinafter, sometimes referred to as fins).
Conventionally, cleaning has been performed using Freon (trademark) to remove non-volatile oil adhering to fins. However, due to recent restrictions on the use of freon gas for the purpose of preserving the global environment, freon cannot be used as a solvent.
For this reason, the present inventors tried to perform ironing processing using volatile oil in order to produce fins without using freon.

[0005]

As described above, by using a volatile oil during the ironing process,
The cleaning of the resulting fins by freon can be dispensed with. However, when ironing is performed using a volatile oil, compared with the case of using a non-volatile oil, the ironing rate indicating the rate at which the metal plate can be extended by ironing decreases, so that the obtained colored perforated hole is obtained. The maximum height of the collar was also found to be reduced. Particularly, recently, it is often necessary to process a metal plate having a high hardness, and the ironing rate is remarkably reduced in conjunction with the use of volatile oil. May be difficult to form. Therefore, an object of the present invention is to provide a method for manufacturing a heat exchanger fin that can provide a through hole with a collar having a predetermined height even when an ironing process is performed using a volatile oil.

[0006]

The present inventors have studied to achieve the above object, and as a result, after forming a small hole in advance, a collar whose diameter is enlarged and formed on the upper surface is formed. By forming a truncated cone or columnar convex portion having substantially the same diameter as the diameter of the through hole by drawing, and then subjecting the convex portion to ironing, a predetermined height can be easily obtained even when volatile oil is used. It has been found that a through hole with a collar can be manufactured, and the present invention has been achieved. That is, the present invention, when forming a colored through-hole in which the periphery of the through-hole is surrounded by a collar of a predetermined height in the metal plate-shaped body, in the metal plate-shaped body, the formed through-hole with a collar to be formed. Drilling of a small hole having a diameter smaller than the opening diameter, and forming a trapezoidal or columnar convex portion having a minimum inner diameter larger than the diameter of the small hole by drawing a metal plate at the periphery of the small hole. And sequentially or simultaneously, then, after adjusting the shape of the small hole formed on the upper end surface of the convex portion to a predetermined shape, a punch having an outer diameter equal to the opening diameter of the through hole with a collar and the punch A method of manufacturing a fin for a heat exchanger, comprising: using a die having an inner diameter equal to the outer diameter of a collar of a through-hole; and subjecting the convex portion to ironing.

[0007]

In general, in the ironing process, the height of the protruding piece which is squeezed by the ironing process affects the collar height of the formed through hole with the collar. On the other hand, in the conventional ironing method shown in FIG. 3, since the projecting pieces are formed by burring, there is a limit to the height of the projecting pieces to be formed. Therefore, the height of the obtained colored through-hole is directly affected by the ironing rate due to the hardness of the metal plate and / or the characteristics of the processing oil used. In this regard, in the present invention, by forming a trapezoidal or columnar convex portion having a small hole formed on the upper surface, the height of the projecting piece to be subjected to the ironing process can be increased in advance. For this reason, a high hardness metal plate and / or
Alternatively, even if the ironing rate at the time of ironing processing is reduced by the use of a volatile oil, a colored through hole having a desired height can be easily formed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in further detail with reference to the drawings. FIG. 1 is a process chart for explaining the present invention, and comprises the following steps. First, a circular small hole 2 is formed in the metal plate 1 [step (a) in FIG. 1]. This small hole 2
Is smaller than the diameter of the opening of the through hole with a collar to be formed. Next, a truncated cone-shaped projection 3 is formed while increasing the diameter of the small hole 2 [step (b) in FIG. 1]. The truncated cone-shaped convex portion 3 has substantially the same diameter as the inner diameter of the through hole with a collar formed by the inner diameter of the bottom surface, and has a small diameter 2 ′ having an enlarged diameter on the upper surface. The small holes 2 ′ opened on the upper surface of the convex portion 3 are difficult to uniformly spread the metal plate 1 when forming the convex portion 3 while expanding the diameter of the small hole 2. Is easily distorted into an elliptical shape.

When the convex portion 3 having the small hole 2 'having such a shape formed on the upper surface is subjected to an ironing process described later,
The height of the collar of the obtained perforated collar is uneven and / or
Or a crack may occur in the collar. For this reason, in the present embodiment, a circular hole 4 having a diameter equal to the long axis length of the small hole 2 'is formed in order to arrange the small hole 2' into a circular shape [FIG.
(C) step). The height of the wall surface 5 of the projection 3 formed in this manner can be made higher than the protruding piece 120 formed by the conventional burring process (the process of FIG. 3A). In the present embodiment, an ironing process is performed on the wall surface 5 of the formed convex portion 3 to form a collar 6 having a desired height [step (d) in FIG. 1]. Further, the collar 6 formed at a desired height is bent at the front end to form a flange 7 (step (e) in FIG. 1).

Next, an apparatus used in the manufacturing method shown in FIG. 1 will be described with reference to FIG. FIG.
In each step shown in FIG. 2, each mold shown in FIG. 2 can be used. That is, in the step of FIG. 1A for forming the small holes 2 in the metal plate 1, a mold shown in FIG. 2A is used. The die includes a piercing punch 10 and a piercing die 11.
It is constituted by and. Next, in the step of FIG. 1B for forming the convex portion 3 while expanding the diameter of the small hole 2 formed by the mold shown in FIG. 2A, the mold of FIG. 2B is used. .
This mold comprises a forming die 12 and a forming punch 14 which moves up and down in a direction perpendicular to the forming stripper 13. The metal plate 1 is sandwiched between a forming die 12 and a forming stripper 13, and a convex portion 3 is formed by a forming punch 14.
Is formed.

In the step (c) of FIG. 1 for shaping the small hole 2 ′ whose diameter is enlarged by the mold of FIG. 2 (B),
The mold shown in FIG. 2C is used. According to this mold, the metal plate 1 is sandwiched between the trimming die 15 and the trimming stopper 16, and the small hole 2 ′ is shaped by the trimming die punch 17 and the trimming punch 25 to form the circular hole 4. Is formed. Thus, the circular hole 4
The wall 3 of the convex portion 3 on which is formed is subjected to the ironing process shown in FIG. 1D using a mold shown in FIG. 2D. According to the mold shown in FIG. 2D, the metal plate 1 is sandwiched between the ironing die 21 and the ironing stripper 20, and the inside of the convex portion 3 is pushed up by the knocking punch 19 by the ironing punch 18. Wall surface 5 of convex portion 3
Then, the collar 6 is formed on the periphery of the through hole.

After the collar 6 has reached the predetermined height, the through hole with the collar is taken out of the ironing die 21 while the ironing punch 18 is lowered by the knockout punch 19. In the through hole with a collar taken out from the ironing die 21, the front end of the collar 6 is bent by a mold shown in FIG. 2 (E) to form a flange 7 (step of FIG. 1 (e)). In such a mold, the tip of the stepped rifrea punch 24 is inserted into the collared through-hole placed on the refrea die 22, and the collar is bent at the step of the rifrea punch 24 to form the collar 7. You. Tsuba 7
The metal-plate-shaped body 1 is pressed by the ejector pin 23 in the through hole with the collar in which is formed, and is taken out of the mold by the rise of the refrea punch 24.

In the above-described embodiment, the process of FIG. 1A for forming the small holes 2 in the metal plate 1 and the convex portions while expanding the diameter of the small holes 2 are described. 1 is formed as a separate step from the step of FIG.
Are formed sequentially, but the drilling of the small holes 2 and the formation of the projections 3 may be performed simultaneously. Further, in the present embodiment, the collar 6 having a desired height can be formed by one-stage ironing processing, and it is not necessary to perform two-stage ironing processing as in the conventional ironing processing method shown in FIG. Needless to say, the ironing process may be performed in two stages as necessary. Further, the smaller the diameter of the small hole 2 formed in the step (a) of FIG.
The height of the wall surface 5 can be increased, but as the diameter of the small hole 2 is reduced, when the convex portion 3 is formed, the distortion of the shape of the enlarged small diameter 2 ′ increases, In some cases, cracks may occur on the wall surface 5. Small holes 2 where such cracks occur
Since the minimum diameter varies depending on characteristics such as hardness of the metal plate 1 to be used, it is preferable to experimentally determine the minimum diameter of the small hole 2 in which the convex portion 3 can be formed without any problem in advance.

[0014]

According to the present invention, a metal plate having a high hardness and / or a volatile oil is used in the ironing process, and even if the ironing rate is significantly reduced, the color-equipped transparent material having a predetermined height can be obtained. Holes can be formed. For this reason, it is possible to sufficiently respond to freon gas regulations and the like.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a process of the present invention.

FIG. 2 is an explanatory diagram for explaining a mold used in the process shown in FIG.

FIG. 3 is an explanatory diagram illustrating a conventional ironing method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal plate 2 small hole 2 ′ enlarged small hole 3 truncated conical projection 4 circular hole 5 wall surface of projection 3 6 collar 7 flange

Claims (1)

(57) [Claims] When forming a collared through-hole in which the periphery of the through-hole is surrounded by a collar of a predetermined height in a metal plate, the opening of the collared through-hole to be formed is formed in the metal plate. Drilling a small hole having a diameter smaller than the hole diameter, and forming a trapezoidal or columnar convex portion having a minimum inner diameter larger than the diameter of the small hole by drawing a metal plate-like body at a peripheral portion of the small hole. Is performed sequentially or simultaneously. Then, after the shape of the small hole formed in the upper end surface of the convex portion is adjusted to a predetermined shape, the punch having the outer diameter equal to the opening diameter of the through hole with the collar and the punch are formed. A method for producing a fin for a heat exchanger, comprising: using a die having an inner diameter equal to the outer diameter of a collar of a hole, and subjecting the convex portion to ironing.